(1) Field of the Invention
This invention relates to a temperature measuring device for an internal-combustion engine, and more particularly to a temperature measuring device for an internal-combustion engine, which device is provided not only with a main temperature sensor intended to measure the temperature of the cooling water, for example, chosen as representing the temperature of the internal-combustion engine but also with a secondary or auxiliary temperature sensor intended as a standby for the aforementioned main temperature sensor.
(2) Description of the Prior Art
The temperature of the internal-combustion engine, particularly when the engine is started or while it is being warmed up, is utilized as a parameter for:
(1) control of the duration of fuel injection in an electronic fuel injection device,
(2) adjustment of the timing for ignition, PA1 (3) control of exhaust gas recirculation, and PA1 (4) control of an opening angle of a throttle valve and/or choke valve in an electronically regulated carburetor.
The temperature of the cooling water for the internal-combustion engine is generally adopted as representing the temperature of the internal-combustion engine.
When the main temperature sensor serving to measure the temperature of the cooling water goes out of order and/or the electric wire interconnecting the main temperature sensor and the electronic control unit is broken or short-circuited, therefore, collection of data on engine temperature is interrupted. Particularly when this mishap arises while the ambient temperature is low, there ensues a problem that the engine will be started or warmed up with difficulty.